a uniform plank weighing 50N and 12m long is pivoted at a point of 4m from one end. A boy weighing 30N sit on the plank 7m from pivot. Where must his elder Brother whose weight is 80N sit to balance the plank horizontally​

In the sport of parasailing, a person is attached to a rope being pulled by a boat while hanging from a parachute-like sail. a rider is towed at a constant speed by a rope that is at an angle of 15 ∘ from horizontal. the tension in the rope is 1900 n. the force of the sail on the rider is 30∘ from horizontal. what is the weight of the rider? express your answer with the appropriate units.

Wavelength, frequency, and energy are related. what happens to a wave as it’s wavelength gets shorter?

A0.580-kg rock is tied to the end of a string and is swung in a circle with a radius of 0.500 meters. the velocity of the rock is 4.50 m/s. what is the centripetal force acting on the rock? 15.5 n 5.22 n 69.8 n 23.5 n